the national security adviserer, secretary kerry, all worning russia it would be a grave mistake to intervene in ukraine when it appeared the diplomatic efforts were failing. president obama came out with a stern warning. here is more of what he had to say. >> throughout this crisis, we have been clear about one fundamental principal. the ukrainian people deserve the opportunity to decide their own future. we urged an end to the violence and urge the ukrainians to stabilize their country for a broad based government and move to elections this spring. >> reporter: now, u.s. officials will continue to monitor the situation closely. i anticipate there will be a flurry of high level phone calls. vice president biden called the prime minister of ukraine yesterday, reiterated the fact the u.s. supports it government there, commended the government on the restraint it has shown so far. u.s. officials have been adamant about the fact this is not a return to cold war tensions between the united states and russia. alex, there is no doubt this is certainly adding to what is an increasingly tense relatio